This invention relates to a control device for a transmission.
Transmission control devices having control units provided in order to eliminate tooth-on-tooth transmission shifting unit positions by adjusting transmission clutches to nominal clutch values are already known.
The purpose of the present invention is to make it more comfortable when eliminating a tooth-on-tooth position. According to the invention, this objective is achieved by the characteristics claimed. Other design features will also be apparent.
The invention starts from a transmission control device having a control unit which is designed in order to eliminate a tooth-on-tooth position of a transmission shifting unit by adjusting a transmission clutch to a nominal clutch value.
It is proposed that, in at least one operating mode, the control unit is designed in order to specify a prescribed clutch value which is independent of an intermediate clutch value setting. By specifying a nominal clutch value, which is independent of the intermediate clutch value setting, a reaction of the transmission clutch to the specification of the nominal clutch value can be better reproduced, so that the control can be better adapted to the transmission clutch. If the control unit is well adapted, the transmission clutch can be controlled more precisely, in particular during a subsequent process to eliminate a tooth-on-tooth position, and comfort is increased as a whole during the elimination of the tooth-on-tooth position.
The term “designed” here is understood to mean specially programmed, equipped and/or planned. The term “nominal clutch value” is understood to mean a clutch value for the transmission clutch which is actually to be set for the transmission clutch. “Prescribed clutch value” is understood to mean a clutch value to be set by the control unit for the transmission clutch, but which is only actually set as the clutch value after a reaction time of the transmission clutch.
The term “clutch value” or the parameters associated therewith is understood to mean a clutch position and/or a clutch torque. Advantageously, in the control unit, a characteristic curve, which relates the clutch position and the clutch torque to one another, is stored. Thus, instead of a clutch position, a clutch torque can also be used, which, by virtue of the characteristic curve, can be converted to a clutch position.
Furthermore, the term “intermediate clutch value setting” is understood to mean a setting by way of which the actual clutch value can be adjusted to a defined intermediate clutch value. Preferably, the intermediate clutch value setting is in the form of a clutch position setting, and is provided in order to set a clutch position, for a defined time interval greater than zero, as accurately as possible to an intermediate clutch position.
The term “intermediate clutch position” is understood to mean a clutch position between a clutch-closed and a clutch-open position, such that the clutch-closed and clutch-open positions are explicitly excluded. A “clutch-open position” is understood to mean a clutch position in which the transmission is fully open. A “clutch-closed position” is understood to mean a clutch position in which the transmission clutch is fully closed. Analogously, as an intermediate clutch value, instead of the intermediate clutch position, an intermediate clutch torque can also be adopted.
It is also proposed to have the control unit designed to specify a prescribed clutch value that is different from the nominal clutch value. In this way, it is simple to find a prescribed clutch value that is different from the intermediate clutch value setting.
In addition, it is proposed to have the control unit designed to specify, as the prescribed clutch value, a clutch-closed position. The clutch-closed position can be set particularly simply independently of the intermediate clutch value setting, and the clutch-closed position is therefore particularly advantageous as the prescribed clutch value.
Advantageously, the control unit is designed to specify only a clutch-closed position and/or a clutch-open position as the prescribed clutch value. This makes it possible, at least in one operating mode, to completely do without the intermediate clutch value setting for eliminating the tooth-on-tooth position.
In a further embodiment it is proposed to design the control unit so that it determines an actuation duration. By virtue of the actuation duration, the intermediate clutch value can be set simply and independently of the intermediate clutch value setting, whereby the tooth-on-tooth position can be eliminated comfortably. Here, “actuation duration” is understood to mean a time interval during which a prescribed clutch value is set, which is different from the clutch-open position.
Advantageously, the control unit is designed to determine the actuation duration as a function of at least one clutch reaction parameter. This enables a particularly advantageous actuation duration to be chosen. Here, “clutch reaction parameter” should be understood to mean a parameter that describes a reaction of the transmission clutch to a specification of a prescribed clutch value, such as a reaction time and/or a displacement speed of the transmission clutch.
It is further proposed that the control unit is designed to define a clutch position in advance. In this way the transmission clutch can set the nominal clutch value accurately, so that the comfort is increased still more. “Define” is here understood to mean calculate or determine.
Preferably, the control unit is designed to define the clutch position in advance as a function of at least one clutch reaction parameter. This enables the clutch position to be defined particularly accurately. Here, “clutch position” should be understood to mean a clutch position actually to be expected. In this context “clutch reaction parameter” should be understood to mean a parameter which describes a reaction of the clutch when a prescribed clutch value of the clutch is changed.
As a further design feature it is proposed to have the control unit comprise an adaptation function designed to adapt at least one clutch reaction parameter individually to the transmission clutch, so that, for example, clutch wear can advantageously be taken into account.
It is particularly advantageous for the adaptation function to be designed for a clutch reaction parameter in the form of a clutch overshoot value. This enables an advantageously accurate determination of the clutch position to take place.
Furthermore, it is advantageous if the adaptation function is designed for a clutch reaction parameter in the form of a clutch reversal time. This enables the determination of the clutch position to be improved still further, so that the tooth-on-tooth position can be eliminated particularly comfortably.
In a particularly advantageous design it is proposed that in at least one further operating mode, the control unit is designed to set the nominal clutch value as the prescribed clutch value. In this way the nominal clutch value can be set accurately over an entire range, whereby in particular a clutch position or clutch torque can also be set, in which the transmission clutch is only slightly closed.
In that case, the control unit is advantageously designed to select the operating mode as a function of the nominal clutch value. This enables the operating mode to be selected simply.
Other advantages will be apparent from the description of the drawings given below. The drawings show an exemplary embodiment of the invention. The drawings, the description and the claims contain numerous characteristics in combination. Those with knowledge of the field will also be able to consider the said characteristics individually as appropriate, and to take them together in other rational combinations.